21234679 has 4 divisors (see below), whose sum is σ = 21752640. Its totient is φ = 20716720.

The previous prime is 21234673. The next prime is 21234691. The reversal of 21234679 is 97643212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21234679 - 2²¹ = 19137527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234673) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 258919 + ... + 259000.

It is an arithmetic number, because the mean of its divisors is an integer number (5438160).

Almost surely, 2^21234679 is an apocalyptic number.

21234679 is a deficient number, since it is larger than the sum of its proper divisors (517961).

21234679 is an equidigital number, since it uses as much as digits as its factorization.

21234679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517960.

The product of its digits is 18144, while the sum is 34.

The square root of 21234679 is about 4608.1101332325. The cubic root of 21234679 is about 276.9163296928.

The spelling of 21234679 in words is "twenty-one million, two hundred thirty-four thousand, six hundred seventy-nine".